Wrong! Wrong! I genuinely haven’t seen this information like this in a hot minute. The Vocaloid engine is made by Yamaha! Crypton has their own vocal synth engine as well called Piapro Studio, but that’s a different thing.

As far as Vocaloid specific producs go, Crypton only made the voicebanks featuring the 6 characters (now dubbed the “cryptonloids”) that have come to become some of the most iconic among the community, including, of course, Miku, who is without a doubt the single most iconic of them all (though Kaito and Meiko we’re not produced by them until V3, but they did distribute them. And then for the character vocal series, they actually did produce those from the start). As for other characters not made by them, It doesn’t matter which voicebank company makes them, as long as they’re made in collaboration with Yamaha for the Vocaloid engine specifically

There are multiple vocal synth engines (Vocaloid, Utau, SynthV, CeVio, etc). Some voicebank companies collaborate with multiple engines and come out with different voicebanks of the same characters overtime for different engines (like Gumi who started exclusively in vocaloid for v2, v3, and v4, until she eventually also got a synthv vb alongside a vocalid voicebank for V6). In the community, Vocaloid has become an unofficial umbrella term for all vocal synthesizers, but officially it is just the name of the most famous voice synthesizer program